1. Field of the Invention
The present invention relates to a construction method of forming a waterproof layer on a bed surface of a concrete bridge (RC, PC, steel bridge) on which an asphalt pavement is formed, a large concrete surface of a rooftop parking and the like on which an asphalt pavement is formed, and a concrete base layer of a water permeable asphalt concrete pavement, and the present invention provides a waterproof sheet in-situ application machine capable of effectively laying a concrete surface with a waterproof sheet in a short time and executing a construction work easily and securely while suppressing occurrence of problems of blistering, wrinkles, and the like.
2. Description of the Related Art
In civil engineering and construction works, a waterproofing work executed to a concrete surface is a very important work which decides the destiny of the civil engineering and construction works. That is, if a waterproofing work is executed imperfectly to a civil engineering structure or a building structure, not only the durable periods the structures are greatly shortened but also all the assets installed in the structures may be lost.
An example of waterproofing mainly in a civil engineering work will be explained below with reference to a concrete bridge (including a concrete structure such as a rooftop parking and the like) and a concrete pavement.
In the concrete bridge, an asphalt pavement is formed on a concrete bed. When, however, rain water passing through the asphalt pavement reaches reinforcing steel rods inside concrete from the surface of the concrete bed, cracks formed in the concrete, and the like, the rain water corrodes the reinforcing steel rods and adversely affects the life of the concrete bridge itself. To cope with this problem, a waterproof layer is formed on the surface of the concrete bed before the asphalt pavement is formed.
A coating type waterproof material, a sheet type waterproof material, and the like are conventionally used as the waterproof layer. In the coating type waterproof material, rubber asphalt melted at a high temperature is flowingly coated onto a bed surface uniformly and cooled by being left as it is to thereby form a rubber asphalt layer, or a coating material, which is made by cutting back synthetic rubber such as chloroprene rubber and the like, is coated onto a bed surface and a solvent is vaporized from the rubber to thereby form a uniform rubber film.
In these coating type waterproof materials, the thickness of a layer which is able to be formed by coating the material at one time is thin, and further it is predicted that the materials are coated unevenly. Thus, to provide the waterproof materials with a sufficient function as a waterproof layer, a plurality of layers must be formed by coating the materials several times with a drying time set each time they are coated in place of coating them only once, which cannot help requiring a complicated job in execution of the work.
In a construction method using the sheet type waterproof material, a waterproof layer is formed by applying a waterproof sheet, which is made by combining rubber-like asphalt and the like with a fiber material such as non-woven fabric and the like, onto the overall surface of a concrete bed using a application agent composed of heated and molten asphalt and the like. In this case, however, since the waterproof sheet is bonded onto the bed surface using the asphalt molten at a high temperature, a dangerous job is required as well as the surrounding of an execution site is adversely affected by offensive odors and the like, and thus the construction method using the sheet type waterproof material is not preferable. Further, the execution of the method is complex and time consuming and requires skill.
In an asphalt pavement having a drainage property (water permeable property) outstandingly constructed recently, since the pavement is formed of a mixture of aggregates, which has a grain size adjusted so that they have fine intervals through which water can pass, and modified asphalt, the pavement has the water permeable property by itself. With this structure, the asphalt pavement contributes to reduce water staying thereon when rain falls, to improve a vehicle traveling performance, and to prevent a hydroplaning phenomenon at the beginning of rainfall. However, since the water permeable pavement does not have sufficient durability by itself, such a structure is employed that a concrete pavement having high durability is formed as a base, and the water permeable pavement is overlaid thereon. This structure intends to guarantee the durability of a road by the bed composed of the concrete pavement and to replace the water permeable overlay layer when the end of life thereof is reached. Conventionally, a tack coat, which is called a “seal layer”, that is, an asphalt emulsion used to enhance the application property of concrete with asphalt, or cut back asphalt is simply applied to the surface of the concrete pavement before a water permeable asphalt pavement is laid on the surface thereof. However, the base composed of the concrete pavement cannot be observed from the surface thereof due to the asphalt layer formed on the upper surface thereof regardless that it guarantees the durability of the road. Therefore, even if defective portions such as cracks are made on the surface of the base, they cannot be detected. In such circumferences, since rain water flows onto the surface of the concrete base at all times through the water permeable pavement, rain water penetrates to the base composed of the concrete pavement from defective portions and corrodes reinforcing steel rods in the base, from which there is a possibility that the life of the road is shortened. This is a reason why prime importance is placed on the waterproofing of the base composed of the concrete pavement.
Ordinarily, however, since a road does not have a limited area but has a long distance and a large area, when a waterproof layer is formed on the road by the construction method employed in a road bridge as described above, serious problems arise in the extension of a construction period, an increase in construction cost, shortage of skilled workers, and the like.
Further, since the number of road bridges and express skyways is increased and the length thereof is made longer, it is increasingly required to apply a waterproof treatment to the large area of them. Under the above circumstances, there is currently expected a novel waterproof layer construction method capable of constructing a long waterproof layer in a short period of time without requiring skilled workers.
Further, in the construction work for a large and long area including a bridge, a rooftop parking, a concrete road, and the like, since there is no means for comprehensively guaranteeing the secure execution of a waterproof layer in the entire area, it is guaranteed by the time-consuming management of respective constructors. Accordingly, there is a great expectation for a waterproof sheet in-situ application machine for easily and securely constructing a waterproof layer because a construction work period can be shortened and a time-consuming management can be omitted thereby.